1. Field of the Invention
The present invention relates generally to hand trucks or dollys adapted to transport a variety of materials. More particularly, my invention relates to hand trucks specifically constructed for fire fighting. The field of the invention includes numerous sub classes within United States Patent Classes 280 and 414.
2. Description of the Prior Art
Numerous prior art hand trucks are known in the prior art. While hand trucks have been employed in fire-fighting, I am aware of no prior art hand truck specifically designed for fire fighting.
Modern fire fighting regulations mandate the use of self-contained breathing apparatus (i.e., SCBA equipment), especially when involving structural entry. In general SCBA apparatus is required for fire fighting where the atmosphere is hazardous or it is expected to be hazardous. When so-equipped, the firefighter can breathe safely even when exposed to noxious fumes and the intense heat. Numerous standards exist regulating the type of SCBA apparatus employed in modern fire fighting. Standards regulating Fire Department use of SCBA air cylinders include the National Fire Protection Association (NFPA) Standard 1500 and NFPA Standard 1404.
Typical SCBA air bottles vary in size. Thirty minute bottles for self contained breathing apparatus charged at approximately 2216 PSI are approximately six inches in diameter and two feet in length. They can weigh fourteen to twenty pounds when fully charged. A larger diameter one hour bottle is over seven inches in diameter and two feet in length. Thus, when a dozen or more bottles are to be transported, a heavy, cumbersome load results.
Numerous SCBA air cylinders are transported into the fire zone. Typically a hand cart or dolly is employed to enable one or two firemen to move the cylinders to the required area. Under typical fire fighting conditions of danger and duress, a number of the bottles may be haphazardly stacked together on the dolly for transport. They may be stacked in layers on conventional hand trucks, assuming a variety of configurations. It is usually difficult to properly arrange relatively heavy loads of air cylinders on conventional hand trucks. As a result, the load may shift when the hand trucks are moved or varied in configuration. For example, the load may shift when several layers of bottles are stacked together on a hand truck that is moved at an angle up a staircase. Load shifting and inadvertent dropping of bottles is particularly common where individual bottles are being removed from the load at different locations within the fire region.
Under the difficult conditions in which the devices are used, numerous other disadvantages have existed with the prior art hand trucks. For example, when the hand truck is heavily loaded with numerous fully-pressurized SCBA cylinders, it is obviously much heavier than when it is unloaded. Difficulties attendant with the moving of a fully loaded dolly up flights of stairs under emergency circumstances should not be underestimated. As a corollary, a hand truck should be adapted for two man operation when loaded, but it should be quickly deployable in the single-man mode when necessary. In general the regulations require that when firefighters employ SCBA cylinders, they must operate in teams of two or more to insure communication with each other. Individual firefighters must be able to readily offer emergency assistance to others on the team.
Since the air bottles are not the only item used in fire fighting, such a hand truck should conveniently store a variety of other tools. For example, forcible entry tools such as axes or pry-bars should be conveniently transportable by the hand truck. Sprinkler wedges, sprinkler tongs, latch straps, hose fittings and adapters should also be readily available for easy access by the fire fighter.
The prior art includes a variety of hand trucks, both patented and unpatented, which are adapted to move a variety of materials and objects.
Typical prior art hand trucks include and elongated rigid frame, with a lower shelf at the bottom, and a wheeled super structure. Stair crawler mechanisms are usually provided to enable the device to negotiate stairs, and such devices have been used in the past for hauling a variety of objects. As seen in the Harper Steel Industrial Hand Truck Catalog 190, pages 15-17, stair crawler hand trucks are known for moving heavy objects over difficult terrain and up stairs. Harper catalog W-9, pages 3-9 shows a variety of hand trucks adapted to carry pressurized gas cylinders. Known hand trucks specifically aimed at such cylinders usually maintain them vertically for stability.
Prior art patents relating generally to hand trucks include U.S. Pat. Des. No. 278,373, and utility U.S. Pat. No. 4,494,626. Rousseau U.S. Pat. No. 3,606,371 issued Sep. 20, 1971 shows a dolly for carrying drum-like devices stacked horizontally. U.S. Pat. No. 4,860,606 issued to Rousseau on Aug. 29, 1989, shows a carrying truck wherein vertically extending items can be rigidly secured together by a ratchet and strap system. Stair crawlers are well known as seen in the latter patent. Numerous patents such as U.S. Pat. No. 4,902,187, show hand trucks for carrying vertically oriented cylinders. Eaglin U.S. Pat. No. 4,899,968, shows a rotary system for handling gas cylinders. U.S. Pat. Nos. 4,281,957, and 4,194,866 also relate to hand trucks.